Post navigation

Stainless steel, the metal bacteria love.

Hospitals love stainless steel, because it looks so “clean”. Unfortunately it is a fantastic media for growing pretty much any pathogen, so it’s a major vector for hospital illnesses. Despite appearances, stainless steel is a filthy metal. Should medical care facilities have prioritized an appearance of cleanliness before testing the reality? Most people outside of the profession would say no, especially given how simple the testing is.

But hospitals in North America have been ripping out their old brass hardware for decades, in response to complaints that it “always looks dirty”. Removing those crusty old doorknobs has put patients and visitors at risk. Brass is a copper alloy, and both copper and silver are self-sterilizing metals (although curiously neither one is listed in the antimicrobial index at this time).

All this is pretty obvious from simple observation in my opinion, but there’s been some research done too. Plow through this quote:

small strips of stainless steel, brass, aluminum, and copper were inoculated with broths of Escherichia coli, Staphylococcus aureus, Streptococcus group D, and Pseudomonas species. […] The results were striking. The copper and brass showed little or no growth, while the aluminum and stainless steel produced a heavy growth of all microbes. How fast did the microbes die on copper and brass? The test was repeated at drying intervals of 15 minutes, I hour, 5 hours, 7 hours, 20 hours, and 24 hours. Brass disinfected itself in seven hours or less, depending on the inoculum size and the condition of the surface of the metal, freshly scoured brass disinfecting itself in one hour. Copper disinfected itself of some microbes within 15 minutes. Aluminum and stainless steel produced heavy growths of all isolates after eight days and growths of most isolates (except Pseudomonas) when I ended that part of my investigation after three weeks-link to original here, with pictures.

If you choose to use stainless steel in your kitchen or lunchbox, that’s fine as long as you scour it thoroughly between uses. I don’t recommend those tiny-necked stainless bottles that can’t be properly cleaned, though – I’ve seen stuff grow in the bottoms of those that looked like kelp, I swear. Inch-long strands of waving black kelp.

And don’t ever touch anything made of stainless steel in a sickroom environment. Research from the EPA and others critical of hospitals’ love affair with stainless shows that superbugs like MRSA and clostridium difficile will happily thrive on stainless steel or aluminum indefinitely, but brass rapidly self-sterilizes without the application of antiseptic toxins or antibiotics… and we all know that these superbugs were created by overuse of antibiotics, right?.

If you want a safer home, office or school environment, never use stainless or aluminum where you could use brass or silver instead. And tell your doctor to change his gloves if he’s going to touch a stainless doorknob, that’s just nasty.